Symptoms
Symptoms, explained in plain words
What a condition usually feels like, how to tell its forms apart, which test settles it, and when to see a doctor.
Thyroid
Thyroid symptoms: the signs in women and men, and when to get tested
An underactive thyroid (hypothyroidism) slows the body down: tiredness, feeling cold, weight gain, constipation, dry skin, low mood and heavy periods. An overactive thyroid (hyperthyroidism) speeds it up: weight loss, a fast heartbeat, feeling hot and sweaty, shaky hands, anxiety and poor sleep. A TSH blood test shows which, if either, it is: in most adults TSH above about 4.0 mIU/L points to an underactive thyroid and below about 0.4 to an overactive one.
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Vitamin B12
Vitamin B12 deficiency symptoms: the signs, the causes and the tests
Low vitamin B12 commonly causes tiredness and breathlessness from anaemia, pale or slightly yellow skin, a sore red tongue and mouth ulcers, and nerve symptoms such as pins and needles, numbness and poor balance, plus memory problems or low mood. NICE treats a total B12 below 180 ng/L as confirmed deficiency and 180 to 350 as possible.
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Kidney disease
Kidney disease symptoms: the signs of kidney damage, and the tests that find it
Early kidney disease usually causes no symptoms, which is why blood and urine tests matter. When symptoms appear, often at a later stage, they include swollen ankles, feet or hands, tiredness, shortness of breath, itchy skin, muscle cramps, poor appetite, feeling sick, peeing more at night, and blood or froth in the pee.
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PCOS
PCOS symptoms: the signs, how it's diagnosed, and why it's now called PMOS
PCOS (polycystic ovary syndrome, renamed PMOS in 2026) commonly causes irregular, infrequent or absent periods, extra hair on the face or body, acne or oily skin, thinning hair on the scalp, weight gain or difficulty losing weight, dark skin patches on the neck or armpits, and difficulty getting pregnant. Some women have only mild symptoms.
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Uric acid and gout
High uric acid and gout symptoms: the signs, the levels, and when it needs a doctor
High uric acid often causes no symptoms at all. Symptoms start when it forms crystals: gout, a sudden, very painful, hot, red and swollen joint, often the big toe, usually starting overnight; kidney stones, with severe pain in the side or lower back; or, after years, hard lumps under the skin. Only a blood test shows your level.
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Fatty liver
Fatty liver symptoms: what grade 1, 2 and 3 mean, the new name MASLD, and what helps
Fatty liver usually causes no symptoms, and most people find out from a scan or blood test done for something else. Some people feel very tired or have a dull ache under the right ribs. Signs such as yellow skin or eyes, a swollen tummy or legs, itching and easy bruising appear only when the liver is badly scarred (cirrhosis).
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Dengue
Dengue symptoms: the early signs, the warning signs that can't wait, and safe care at home
Dengue usually starts 4 to 10 days after the mosquito bite with a sudden high fever, a severe headache, pain behind the eyes, muscle, joint and bone pain, nausea or vomiting, and sometimes a rash. Symptoms last 2 to 7 days. Watch closely as the fever goes: severe tummy pain, repeated vomiting or bleeding then need emergency care.
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Typhoid
Typhoid symptoms: the fever pattern, the danger signs, and which test to trust
Typhoid usually starts 6 to 30 days after eating or drinking something contaminated, with a fever that rises day by day to 39 to 40°C (103 to 104°F), lasting more than 3 days. Headache, weakness, poor appetite, tummy pain, constipation or diarrhoea and a cough are common, and some people get flat pink spots. It needs antibiotics.
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Lab tests, explained in plain words
All lab test guides
CBC
CBC test: full form, normal ranges and what your blood count means
CBC stands for complete blood count. It measures your red blood cells and haemoglobin (which carry oxygen), white blood cells (which fight infection) and platelets (which help blood clot). Typical adult ranges are haemoglobin 13.5 to 17.5 g/dL in men and 12.0 to 15.5 in women, white cells 4,000 to 11,000 per µL, and platelets 150,000 to 450,000 per µL.
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HbA1c
HbA1c test: normal range, chart and what your result means
A normal HbA1c is below 5.7% (39 mmol/mol). 5.7% to 6.4% (39 to 47 mmol/mol) is the prediabetes range, and 6.5% (48 mmol/mol) or higher is in the diabetes range, which a doctor confirms with a second test. HbA1c shows your average blood sugar over about three months, and you don't need to fast for it.
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Lipid profile
Lipid profile test: normal cholesterol, HDL, LDL and triglyceride levels
For most adults, desirable levels are total cholesterol below 200 mg/dL (5.2 mmol/L), LDL ("bad") cholesterol below 100 mg/dL (2.6 mmol/L), HDL ("good") cholesterol of 40 mg/dL or more in men and 50 or more in women, and triglycerides below 150 mg/dL (1.7 mmol/L). People with diabetes or heart disease are usually given lower LDL targets.
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TSH
TSH test: normal range, full form and what high or low TSH means
A normal TSH (thyroid-stimulating hormone) for most adults is about 0.4 to 4.0 mIU/L, though labs differ slightly. A higher TSH usually means an underactive thyroid, because the brain is pushing a slow thyroid harder; a lower TSH usually means an overactive one. Doctors read it with free T4, and ranges differ in pregnancy and older age.
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Vitamin D
Vitamin D test: normal levels, deficiency symptoms and where to get it
Vitamin D is measured as 25-hydroxyvitamin D. Below 20 ng/mL (50 nmol/L) is deficient and below 12 ng/mL (30 nmol/L) is severely low. Most experts consider 20 ng/mL or more enough for bone health, and many labs print 30 to 100 ng/mL as the reference range. Above about 50 ng/mL brings no extra benefit, and very high levels can be harmful.
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Creatinine
Creatinine test: normal range, high levels and what your result means
A normal serum creatinine is roughly 0.7 to 1.3 mg/dL (62 to 115 µmol/L) for adult men and 0.6 to 1.1 mg/dL (53 to 97 µmol/L) for adult women, though each lab prints its own range. Creatinine is a waste product your kidneys filter out, so a higher number can mean they're filtering less. Doctors read it with your eGFR.
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Ferritin
Ferritin test: normal levels, low and high ferritin, and what your result means
A typical adult ferritin range is about 24 to 336 ng/mL for men and 11 to 307 ng/mL for women, though labs differ. Below 15 ng/mL means your iron stores are used up, and 15 to 30 is often low enough to cause symptoms. Ferritin also rises with inflammation, so doctors read it alongside your haemoglobin and iron tests.
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